Lid placement and seating detector

ABSTRACT

An inspection station for checking the correct placement of a lid on a filled plastic container that is traveling on a conveyor that includes: a detector plate assembly ( 16 ) that has a flat surface ( 32 ) and an inclined surface ( 44 ); a support assembly ( 18 ); a mounting assembly ( 22 ) for attaching the detector plate assembly ( 16 ) to the support assembly ( 18 ) for holding the flat surface ( 32 ) in a predetermined parallel relationship with a top or conveying surface ( 30 ) of the conveyor ( 12 ) while simultaneously allowing vertical displacement thereof; a first sensor ( 54 ) for detecting the presence of a plastic container ( 20 ) to be checked or inspected; a second sensor ( 56 ) for sending a signal when the detector plate is within a selected range of vertical displacement. In operation the plastic container traveling horizontally on the conveyor first contacts the inclined surface thereby vertically displacing the detector plate assembly ( 16 ) sufficiently for subsequently allowing the flat surface ( 32 ) to contact a top surface of the plastic container for allowing the second sensor ( 56 ) to cooperate with a notched bar ( 58 ) to determine whether the vertical displacement is outside of the selected range.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] With regard to the classification of art, this invention isbelieved to be found in the general class entitled Package Making andmore particularly to those subclasses pertaining to an apparatus forchecking the placement of lids on pails.

[0003] 2. Description of Related Art

[0004] Lid checking or detecting apparatus are well known in the priorart. Some examples of the known prior art disclosing lid checking ordetecting devices are: U.S. Pat. No. 2,883,810 that issued to Gieskiengon Apr. 28, 1959; U.S. Pat. No. 3,411,621 that issued to Gerben on Nov.19, 1968; U.S. Pat. No. 3,460,314 that issued to Keas on Aug. 12, 1969;U.S. Pat. No. 3,477,197 that issued to Budz on Nov. 11, 1969; U.S. Pat.No. 4,773,204 that issued to Rydstrom on Sep. 27, 1988; U.S. Pat. No.4,872,300 that issued to Luke on Oct. 10, 1989; U.S. Pat. No. 4,724,384that issued to Castovilly et al on Feb. 9, 1988; U.S. Pat. No. 4,852,745that issued to Lemaire et al on Aug. 1, 1989; and U.S. Pat. No.5,438,814 that issued to Lovett et al on Aug. 8, 1995. It has bendetermined that there is still a need for a lid checking and detectingapparatus that simultaneously detects the existence of a lid and/or thecorrect seating of the lid on a pail or container. It has also beendetermined that this needed apparatus must also operate when and whilethe pail or container is moving continuously on an associated conveyorand at package line speeds. The present invention solves the aboveidentified needs while checking all seating conditions along theperipheral edge of the pail or container.

SUMMARY OF THE INVENTION

[0005] One embodiment of the present invention may be briefly describedas: an apparatus for checking the correct placement of a lid on a filledplastic container that is traveling on a conveyor that includes: a). adetector plate assembly that has a flat surface and an inclined surface;b) a support assembly c) a means for mounting the detector plateassembly to the support assembly whereby the flat surface of thedetector plate is held in a predetermined parallel relationship with atop or conveying surface of the conveyor while simultaneously allowingvertical displacement thereof; d) a first sensor for detecting thepresence of a plastic container to be checked or inspected; a secondsensor for sending a signal when the detector plate is within a selectedrange of vertical displacement; and wherein the plastic containertraveling horizontally on the conveyor first contacts the inclinedsurface thereby vertically displacing the detector plate assemblysufficiently for subsequently allowing the flat surface to contact a topsurface of the plastic container and the second sensor also determinesand sends a different signal whether the vertical displacement isoutside the selected range .

[0006] The present invention may also include the following additionalfeatures individually or in combination: 1) a detector plate assemblyhaving a flat surface that is momentarily overlapping at least 80percent of the area interior of the peripheral outline of the topsurface of the container as and when the container is traveling in ahorizontal direction on the conveyor; 2) the means for mounting thedetector plate to the support assembly includes a pair of elongatedshafts that are selectively spaced in a predetermined parallelrelationship on the support assembly; 3) the support assembly includes apair of low friction ball bushing assemblies that are selectively spacedin a predetermined parallel relationship on the detector plate assemblyfor vertical movement on the pair of elongated shafts, 4) at least oneadjusting assembly for selectively aligning the flat surface with thetop surface of the plastic container prior to their contact; 5) thesecond sensor being a proximity switch that is mounted and carried onthe adjusting assembly for sending the signal by detecting a notchedportion of the detector plate assembly.

[0007] In addition to the above summary, the following disclosure isintended to be detailed to insure adequacy and aid in the understandingof the invention. However, this disclosure, showing particularembodiments of the invention, is not intended to describe each newinventive concept that may arise. These specific embodiments have beenchosen to show at least one preferred or best mode for an apparatus ofthe present invention. These specific embodiments, as shown in theaccompanying drawings, may also include diagrammatic symbols for thepurpose of illustration and understanding.

BRIEF DESCRIPTION OF THE DRAWING

[0008]FIG. 1 represents a front elevation of a an apparatus for checkingthe correct placement of a lid on a filled plastic container travelingon a conveyor

[0009]FIG. 2 represents a right side elevation thereof.

[0010]FIG. 3 represents a top elevation thereof, this view being shownin an enlarged scale.

[0011]FIG. 4 represents an isolated view of the second sensor, this viewis taken in the same direction as FIG. 2 and in an enlarged scale.

[0012]FIG. 5 represents an isolated view of the second sensor, this viewis taken in the same direction as FIG. 4 and showing a no lid condition.

[0013]FIG. 6 represents an isolated view of the second sensor, this viewis taken in the same direction as FIG. 4 and showing either a high, orcocked, or unseated lid condition.

[0014] In the following description and in the appended claims, variousdetails are identified by specific names for convenience. These namesare intended to be generic in their application while differentiatingbetween the various components. The corresponding reference numbersrefer to like members throughout the several figures of the drawing.

[0015] The drawings accompanying and forming a part of thisspecification disclose details of construction for the sole purpose ofexplanation. It is to be understood that structural details may bemodified without departing from the concept and principles of theinvention as claimed. This invention may be incorporated into otherstructural forms than shown.

DETAILED DESCRIPTION OF THE INVENTION

[0016] Referring to the drawings FIGS. 1 through 6, an apparatus orassembly for checking the correct placement of a lid on a filled plasticcontainer is generally identified as 10. The assembly 10 is removableattached to a conveyor 12 by way of a plurality of threaded fasteners14. The assembly 10 includes a detector plate assembly 16 and at leastone support assembly 18. It has been found that mounting the assembly 10to the conveyor 12 in cantilever fashion, as more clearly seen in FIG.2, provides an arrangement for allowing easy removal of a container 20if and when necessary. Of course the support assembly 18 must besufficiently sized and shaped for supporting the anticipated cantileverloading. One non-limiting example of a support assembly 18 is a channelshaped upright member 24 that is removably attached to the side rail 26of the conveyor 12. In this example, spacer blocks 28 may be requiredfor positioning a center of the detector plate assembly 18 over thecenter of the conveyor. However it is to be noted that the assembly 10may also include front and rear support assemblies 18 that are arrangedfor straddling the conveyor 12.

[0017] The assembly 10 further includes a means for the mounting,identified as 22. The means for mounting 22 attaches the detector plateassembly 16 to the support assembly 18. This means for the mounting 22must provide vertical guidance for the detector plate assembly 16 duringany movement and/or adjustment in the direction of arrow A. The verticalguidance must maintain a predetermined parallelism in two directionsbetween the conveying surface 30 of the conveyor 12 and a flat surface32 of the detector plate assembly 16 during any movement in thedirection of arrow A. One direction of the predetermined parallelism isin the direction of container travel that is depicted by arrow B and asecond direction that is transverse to arrow B and parallel to the axisof conveyor rollers. One non-limiting example of a means for mounting 22is a pair of elongated shafts 34 that are selectively spaced andsupported in a predetermined parallel relationship on the channel member24 of the support assembly 18. A pair of end blocks 38 supports each endof the elongated shafts 34. The detector plate assembly 16 is guided onthe elongated shafts 34 by commercially available linear anti-frictionball bushings 40 that are housed in bushing blocks 42. In this example,it is preferred that the elongated shafts 34 be of the precision typeand have a hardened surface for resisting premature wear.

[0018] The detector plate assembly 16 further includes an inclinedsurface or ramp 44. The connection of the inclined surface or ramp 44 tothe flat surface 32 should be a smooth transition absent any raisedwelds and the like. The inclined surface 44 is formed at a predeterminedincluded angle C with respect to the flat surface 32. One non-limitingexample of a range for the included angle C is between 25 and 35 arcdegrees. The detector plate assembly 16 preferably is made of a weldedsheet metal construction that includes; an end gusset 46, at least oneintermediate gusset 48, a front flange 50, a rear flange 52, and an endflange 53 that must be of sufficient size and thickness for minimizingany deflection thereof during use while also minimizing it's weight.

[0019] The assembly 10 includes a first sensor 54 and second sensor 56.The first sensor 54 is employed for sensing a container 20 or pail thatis to be checked for the proper placement and seating of its lid. Onenon-limiting example of a first sensor 54 is a commercially availablephotocell. The second sensor 56 is employed for detecting the properplacement of the lid on the container 20.

[0020] When the assembly 10 of the present invention is to be used withcontainers having a fixed or constant height, the first sensor 54 andthe second sensor 56 may be removably attached to the channel member 24by and with a common bracket member 57 One non-limiting example of asecond sensor 56 is a commercially available proximity switch thatsenses a metallic object and then sends a signal. In this non-limitingexample the second sensor 56 senses the presence of an elongatedmetallic bar 58 that is removably and adjustably mounted to the rearflange 52 of the detector plate assembly 16. The elongated metallic bar58 has a notched area 60 formed therein. The notched area 60 should belarger than the diameter of the sensing face of the second sensor by apredetermined amount. The elongated metallic bar 58 is attached to therear flange 52 by at least two elongated through apertures 62 or slottedholes for allowing the proper adjustment of the notched area 60 withrespect to the second sensor 56. The adjustment will be discussed below.

[0021] In a preferred non-limiting arrangement, the present invention isadapted for handling a range of heights of the container 20. In thispreferred arrangement the assembly 10 of the present invention furtherincludes an adjusting assembly 64. One non-limiting example for anadjusting assembly 64 includes a jacking screw 66 that is journalled inpair of bearing blocks 68. A jacking block 70 is sized and threaded forvertical advancement as and when the jacking screw 66 is turned in aclockwise or counter-clockwise direction by handle 72. It is preferredthat the adjusting assembly 64 include a locking device 74 formaintaining a desired set position during operation of the packagingline. A stop block 76 is mounted to the detector plate assembly 16. Thestop block 76 rests on top of the jacking block 70 so that a desiredlower limit is provided for the detector plate assembly 16. Thisarrangement allows the detector plate assembly 16 to move upwardly apredetermined vertical distance when a container 20 is passingthereunder and in sliding abutment with the flat surface 32. Theoperation of this adjusting assembly will be also discussed below.

[0022] The set up of the assembly 10 having an adjusting assembly 64includes the steps of: First, placing a container 20 having a properlyplaced lid seated thereon on the conveying surface of a stopped conveyor12 so that the flat surface 32 is slightly below the raised portions ofthe top surface 78 of container 20; Second, manually lifting thedetector plate assembly 16 and placing the container 20 between theconveying surface of the stopped conveyor 20 and the detector plateassembly 16 so that a least 80 percent of the area within the perimeteroutline of a top surface 78 of the container 20 and the area of the flatsurface 32 are overlapping and while having any portions of the topsurface 78 to be checked abutting the flat surface 32; Third, rotatingthe handle 72 of the adjusting assembly so that the center axis of thesecond sensor 56 is aligned with the center of the notched area 60 ofthe elongated metallic bar 58, more clearly seen in FIG. 4, so that achange of signal occurs at the switching contacts of the second sensor56. Fourth, locking the adjusting assembly 64 at the desired position bytightening the locking device 74.

[0023] In operation, the containers or pails 20 travel on the conveyingsurface 30 of the conveyor 12 in a substantially horizontal direction,as depicted by arrow B. A leading edge of the top surface 78 of thecontainer 20 contacts the inclined surface 44 of the detector plateassembly 16. This contact creates a cam-like action that lifts thedetector plate assembly 16, in the direction of arrow A, sufficiently toallow the container to pass under the flat surface 32 while maintaininga parallel relationship with the conveying surface 30 of the conveyor12. It is preferred that the area of the flat surface 32 and at least 80percent of area with the peripheral outline of the top surface 78momentarily overlap when and while the container is continuously movingthereunder. As the first sensor 54 detects the container 20, the controlcircuit begins to look for a signal from the second sensor 56. Thesecond sensor 56 will provide an “ACCEPT” signal if the lid is properseated on the container 20 and centered with the notched area 60, moreclearly seen in FIG. 4, The second sensor will send a “REJECT” signalwhen either no lid is present, more clearly seen in FIGS. 2 and 5 or ifthe lid in not properly seated on the container 20, more clearly seen inFIG. 6. The present invention will also detect a lid that is eithercocked or a lid that has only a small portion that is not seatedproperly. It has been found that the present invention will reliablydetect lid height variations that are as little as 1.6 mm (0.063 in.)beyond the “ACCEPT” range. The “REJECT” signal is a result of the secondsensor detecting the raised surface 80 on either side of the notchedarea 60 of the elongated metallic bar 58. The output signal from secondsensor 56 may be either connected to an alarm device or used by apacking line control circuit sequencer for removal or inspection of anyrejected containers.

[0024] The steps for the set-up of the present invention when thecontainers to be inspected are always the same height include: First,manually lifting the detector plate assembly 16 and placing thecontainer 20 between the conveying surface of the stopped conveyor 20and the detector plate assembly 16 so that a least 80 percent of thearea of a top surface 78 of the container 20 and the area of the flatsurface 32 are overlapping and with the raised portions of the topsurface 78 abutting the flat surface 32; Second, loosening the fasteners82 that mount the elongated metallic bar 58; Third, slide the elongatedbar 58 along the elongated apertures 62 so that the second sensor 56 andthe notched area 60 are aligned as discussed above; Fourth, tighten thefasteners 82 so that the elongated bar 58 is locked in place. Theoperation thereafter is similar to that described above.

[0025] It is anticipated that sensing means other than the particulartype described in connection with the first sensor 54 and the secondsensor 56 may be used. It is also anticipated that the mountinglocations for the first sensor 54 and the second sensor may be alteredto suit a particular application.

[0026] It is to be noted that the present invention may also be usedwith intermittent motion or indexing conveyors.

[0027] Directional terms such as “front”, “back”, “in”, “out”,“downward”, “upper”, “lower” and the like may have been used in thedescription. These terms are applicable to the embodiments shown anddescribed in conjunction with the drawings. These terms are merely usedfor the purpose of description in connection with the drawings and donot necessarily apply to the position in which the present invention maybe used.

[0028] While these particular embodiments of the present invention havebeen shown and described, it is to be understood that the invention isnot limited thereto and protection is sought to the broadest extent thatthe prior art allows.

What is claimed is:
 1. An apparatus for checking the correct placementof a lid on a filled plastic container traveling on a conveyorincluding: a). a detector plate assembly including a flat surface and aninclined surface; b) support assembly; c) a means for mounting thedetector plate assembly to the support assembly whereby the flat surfaceof the detector plate being held in a predetermined parallelrelationship with top surface of the conveyor while simultaneouslyallowing vertical displacement thereof; d) a first sensor for detectingthe presence of a plastic container to be checked; d) a second sensorfor sending a signal when the detector plate is within a selected rangeof vertical displacement; and wherein the plastic container travelinghorizontally on the conveyor first contacts the inclined surface therebyvertically displacing the detector plate assembly sufficiently forsubsequently allowing the flat surface to contact a top surface of theplastic container wherein the second sensor determines and sends asignal whether the vertical displacement is outside the selected range.2. An apparatus as recited in claim 1 wherein the area of the flatsurface momentarily overlaps at least 80 percent of an area within aperipheral outline of the top surface of the plastic container as andwhen the plastic container is traveling horizontally on the conveyor. 3.An apparatus as recited in claim 1 wherein the means for mounting thedetector plate to the support assembly includes a pair of elongatedshafts that are selectively spaced in a predetermined parallelrelationship on the support assembly.
 4. An apparatus as recited inclaim 2 wherein the means for mounting the detector plate to the supportassembly includes a pair of elongated shafts that are selectively spacedin a predetermined parallel relationship on the support assembly.
 5. Anapparatus as recited in claim 3 wherein the means for mounting thedetector plate to the support assembly further includes a pair of ballbushing assemblies that are selectively spaced in a predeterminedparallel relationship on the detector plate assembly for verticalmovement on the pair of elongated shafts.
 6. An apparatus as recited inclaim 4 wherein the means for mounting the detector plate to the supportassembly further includes a pair of ball bushing assemblies that areselectively spaced in a predetermined parallel relationship on thedetector plate assembly for vertical movement on the pair of elongatedshafts.
 7. An apparatus as recited in claim 1 that further includes atleast one adjusting assembly for selectively aligning the flat surfacewith the top surface of the plastic container.
 8. An apparatus asrecited in claim 2 that further includes at least one adjusting assemblyfor selectively aligning the flat surface with the top surface of theplastic container.
 9. An apparatus as recited in claim 3 that furtherincludes a least one adjusting assembly for selectively aligning theflat surface with the top surface of the plastic container.
 10. Anapparatus as recited in claim 4 that further includes a least oneadjusting assembly for selectively aligning the flat surface with thetop surface of the plastic container.
 11. An apparatus as recited inclaim 5 that further includes a least one adjusting assembly forselectively aligning the flat surface with the top surface of theplastic container.
 12. An apparatus as recited in claim 6 that furtherincludes a least one adjusting assembly for selectively aligning theflat surface with the top surface of the plastic container.
 13. Anapparatus as recited in claim 1 wherein the second sensor is mounted onan adjusting assembly, the adjusting assembly being adapted forselectively aligning the flat surface with the top surface of theplastic container for sending the signal.
 14. An apparatus as recited inclaim 2 wherein the second sensor is mounted on an adjusting assembly,the adjusting assembly being adapted for selectively aligning the flatsurface with the top surface of the plastic container for sending thesignal.
 15. An apparatus as recited in claim 3 wherein the second sensoris mounted on an adjusting assembly, the adjusting assembly beingadapted for selectively aligning the flat surface with the top surfaceof the plastic container for sending the signal.
 16. An apparatus asrecited in claim 5 wherein the second sensor is mounted on an adjustingassembly, the adjusting assembly being adapted for selectively aligningthe flat surface with the top surface of the plastic container forsending the signal.
 17. An apparatus as recited in claim 1 wherein thesecond sensor is a proximity switch that detects a notched portion ofthe detector plate assembly. for sending the signal.
 18. An apparatus asrecited in claim 2 wherein the second sensor is a proximity switch thatdetects a notched portion of the detector plate assembly. for sendingthe signal.
 19. An apparatus as recited in claim 3 wherein the secondsensor is a proximity switch that detects a notched portion of thedetector plate assembly. for sending the signal.
 20. An apparatus asrecited in claim 16 wherein the second sensor is a proximity switch thatdetects a notched portion of the detector plate assembly. for sendingthe signal.